Some our customer has a new order but has been stopped long time ago (2012) which ENIG PCB in our raw material stock that are date code xx12 (still be vacuum sealed with silica gel) so,Will there be any risk or not? Help me please.

You should be fine! best practice for a situation like this would be to run a solder sample, either flux it and run through wave, or screen print, don't place parts and run through reflow. look for proper wetting characteristics if you see de-wetting/non-wetting... don't use them. I always like to put a quality alert in the job packet (doc set) as well to warn the production team to watch folder solderability issue... Oh ya,, Bake the board before you process them to drive off any moisture they may have absorbed.